Smooth Draping Layer for Rendering Vector Data on Complex Three Dimensional Objects

ABSTRACT

Systems and methods for rendering vector data in conjunction with a three-dimensional model are provided. In particular, a smooth transparent draping layer can be generated and rendered overlaying the three-dimensional model. The vector data can be texture mapped to the smooth transparent draping layer such that the vector data appears to be located along a surface in the three-dimensional model. The three-dimensional model can be a model of a geographic area and can include terrain geometry that models the terrain of the geographic area and building geometry that models buildings, bridges, and other objects in the geographic area. The smooth transparent draping layer can conform to the surfaces defined by the terrain geometry. The vector data can be texture mapped to the smooth transparent draping layer such that the vector data appears to be located along the surface of the terrain geometry but can be occluded by the building geometry.

FIELD

The present disclosure relates generally to computer graphics and moreparticularly, to rendering vector data in conjunction withthree-dimensional objects in a computer graphics application.

BACKGROUND

Improvements in computer processing power and broadband technology haveled to the development of interactive three-dimensional models. Forinstance, interactive geographic information systems can provide for thenavigating and displaying of three-dimensional representations ofgeographic areas. A user can navigate the three-dimensionalrepresentation by controlling a virtual camera that specifies whatportion of the three-dimensional representation is rendered andpresented to a user.

The three-dimensional model can include geometry and texture that istexture mapped to the geometry. For instance, a three dimensional modelof a geographic area can include terrain geometry that models theterrain of the Earth in addition to building geometry that modelsbuildings, bridges, and other objects. Geographic imagery, such asaerial or satellite imagery, and other imagery can be texture mapped tothe terrain geometry and/or the building geometry to provide a morerealistic model of the geographic area.

Vector data can be rendered in conjunction with the three dimensionalmodel. Vector data can include data such as labels, overlays, roadoverlays, text, and other data. One approach to rendering vector data inconjunction with the three-dimensional model is to render the vectordata in the three-dimensional space defined by the model. This canrequire complex projection calculations and can require tracing manyrays to place the vector data correctly relative to the surface of thethree-dimensional model. It can also be difficult to consistently placethe vector data correctly using this approach.

Another approach to rendering vector data in conjunction with thethree-dimensional model is to texture map the vector data to thethree-dimensional model. However, certain objects within thethree-dimensional model can include lumpy, edgy and awkward geometry. Asa result, texture mapping vector data directly to the three-dimensionalmodel can lead to the vector data becoming unreadable or placedincorrectly.

SUMMARY

Aspects and advantages of the invention will be set forth in part in thefollowing description, or may be obvious from the description, or may belearned through practice of the invention.

One exemplary aspect of the present disclosure is directed to acomputer-implemented method of rendering vector data in conjunction witha three-dimensional model. The method includes presenting a viewport ina user interface on a display device and rendering a three-dimensionalmodel in the viewport. The method further includes rendering atransparent draping layer overlaying the three-dimensional model andtexture mapping the vector data to the transparent draping layer suchthat the vector data appears to be located along a surface of thethree-dimensional model in the viewport.

Other exemplary aspects of the present disclosure are directed tosystems, apparatus, non-transitory computer-readable media, userinterfaces and devices for rendering vector data in conjunction with athree-dimensional model, such as a three-dimensional model of ageographic area.

These and other features, aspects and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustrateembodiments of the invention and, together with the description, serveto explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth in the specification, which makes reference to the appendedfigures, in which:

FIG. 1 depicts a simplified representation of a three-dimensional modelof a scene according to an exemplary embodiment of the presentdisclosure;

FIG. 2 depicts a portion of a three-dimensional model presented in aviewport according to an exemplary embodiment of the present disclosure;

FIG. 3 depicts a flow diagram of an exemplary method for renderingvector data in conjunction with a three-dimensional model according toan exemplary embodiment of the present disclosure;

FIG. 4 depicts a flow diagram of an exemplary rendering method forrendering a smooth transparent draping layer according to an exemplaryembodiment of the present disclosure;

FIG. 5 depicts a flow diagram of an exemplary method for generating asmooth transparent draping layer according to an exemplary embodiment ofthe present disclosure; and

FIG. 6 depicts an exemplary computing system according to an exemplaryembodiment of the present disclosure.

DETAILED DESCRIPTION

Reference now will be made in detail to embodiments of the invention,one or more examples of which are illustrated in the drawings. Eachexample is provided by way of explanation of the invention, notlimitation of the invention. In fact, it will be apparent to thoseskilled in the art that various modifications and variations can be madein the present invention without departing from the scope or spirit ofthe invention. For instance, features illustrated or described as partof one embodiment can be used with another embodiment to yield a stillfurther embodiment. Thus, it is intended that the present inventioncovers such modifications and variations as come within the scope of theappended claims and their equivalents.

Generally, the present disclosure is directed to systems and methods forrendering vector data (e.g. text, labels, overlays, roads, etc.) inconjunction with a three-dimensional model. In particular, a smoothtransparent draping layer can be generated and rendered overlaying thethree-dimensional model. The smooth transparent draping layer canconform to one or more surfaces of the three-dimensional model. Thevector data can be texture mapped to the smooth transparent drapinglayer such that the vector data appears to be located along a surface inthe three-dimensional model. In this manner, the systems and methods ofthe present disclosure can have a technical effect of reducing visualartifacts that may result from directly mapping the vector data tosurfaces in the three-dimensional model with complex geometry (e.g. hardedges, bumps, etc.).

In one embodiment, the three-dimensional model can be a model of ageographic area. The three-dimensional model can include terraingeometry that models the terrain of the geographic area and buildinggeometry that models buildings, bridges, and other objects in thegeographic area. The three-dimensional model can be a polygon mesh (e.g.a triangle mesh) that is generated, for instance, using stereoreconstruction techniques. During rendering of a representation of thegeographic area, a smooth transparent draping layer can be renderedoverlaying the terrain geometry. For instance, the smooth transparentdraping layer can conform to the surfaces defined by the terraingeometry. The vector data can be texture mapped to the smoothtransparent draping layer such that the vector data appears to belocated along the surface of the terrain geometry. In particularaspects, the smooth transparent draping layer and the vector data can berendered such that the vector data can be occluded by the buildinggeometry in the representation of the geographic area.

Various rendering algorithms can be used to render a scene depictingvector data in conjunction with the three-dimensional model according toexemplary aspects of the present disclosure. For instance, in oneembodiment, the smooth transparent draping layer can be rendered with adepth offset relative to the terrain geometry. According to anotherexemplary embodiment, the rendering algorithm can render buildinggeometry with a first stencil value in a stencil buffer associated withthe scene. The terrain can then be rendered with a second stencil valuein the stencil buffer. The depth buffer can be cleared for all pixels inthe scene associated with the second stencil value. The transparentdraping layer can then be rendered with depth write and depth test bothon. This provides for the rendering of the transparent draping layer infront of the terrain geometry. However, the transparent draping layercan still be occluded by building geometry in areas where the buildinggeometry is in front of the terrain geometry.

The smooth transparent draping layer can be generated from thethree-dimensional model. For instance, in one implementation, thetransparent draping layer can be generated by accessing athree-dimensional model. The terrain geometry can be extracted from thethree-dimensional model. The terrain geometry can be smoothed accordingto a suitable smoothing algorithm (e.g. a Gaussian smoothing algorithm)to generate smooth terrain geometry. The transparent draping layer canthen be generated from the smooth terrain geometry, for instance, usinga suitable meshing algorithm. A transparent draping layer can begenerated for each level of detail of the three-dimensional model. Inaddition, the transparent draping layer for each level of detail can bespatially partitioned into a plurality of geospatial data objects andstored in a hierarchical tree data structure.

With reference now to the FIGS., exemplary embodiments of the presentdisclosure will now be discussed in detail. FIG. 1 depicts a simplifiedrepresentation of an exemplary three-dimensional model 110 of a scene100 according to an exemplary embodiment of the present disclosure.While FIG. 1 illustrates a two-dimensional representation of thethree-dimensional model for purposes of illustration and discussion, oneof ordinary skill in the art, using the disclosures provided herein,will recognize that two-dimensional representations can berepresentative of three-dimensional elements.

The three-dimensional model 110 can be representative of a geographicarea. For instance, the three-dimensional model 110 can be a model of ageographic area provided by a geographic information system, such as theGoogle Maps™ mapping application and the Google Earth™ virtual globeapplication provided by Google Inc. The three-dimensional model 110 canalso be other suitable three-dimensional models.

The three-dimensional model 110 can be a polygon mesh, such as trianglemesh or other mesh. The mesh can include a plurality of polygons (e.g.triangles) that are used to model the geometry of a geographic area. Inone example, the three-dimensional model 110 can be a stereoreconstruction generated from aerial or satellite imagery of thegeographic area. The three-dimensional model 110 can include terraingeometry 112 and building geometry 114. The terrain geometry 112 canmodel the terrain of the geographic area. The building geometry 114 canmodel building and other objects in the geographic area.

Vector data 140 (e.g. text, overlays, roads, etc.) is rendered inconjunction with the three-dimensional model 110. In particular, thevector data 140 is texture mapped to a smooth transparent draping layer120. The smooth transparent draping layer 120 is a transparent layer(i.e. invisible layer) that overlays the surface of the terrain geometry112. In particular, the smooth transparent draping layer 120 conforms tothe surface of the terrain geometry 112. In FIG. 1, the smoothtransparent draping layer 120 does not conform or overlay the surfacesdefined by the building geometry 114.

The geometry of the smooth transparent draping layer 120 has beensmoothed, for instance, by a suitable smoothing algorithm (e.g. aGaussian smoothing algorithm) so that the smooth transparent drapinglayer 120 provides a suitable smooth surface for texture mapping thevector data 140. During rendering of three-dimensional model 110, thevector data 140 is texture mapped to the smooth transparent drapinglayer 120 so that it appears that the vector data 140 is located along asurface of the three-dimensional model 110, such as along the terraingeometry 112 of the three-dimensional model 110. The building geometry114 can occlude at least a portion any vector data 140 texture mapped tothe smooth transparent draping layer 120.

The three-dimensional model 110 can be rendered from the perspective ofa virtual camera 130. The virtual camera 130 defines whatthree-dimensional data to display to a user, for instance in a viewportpresented in a user interface on a display device. A user can navigatethe three dimensional model 110 by navigating the virtual camera 130relative to the three-dimensional model 110.

FIG. 2 depicts a view of a portion of the three-dimensional model 110rendered in a viewport 215 presented in a user interface 205 on adisplay device 210. The three-dimensional model 110 can be presentedfrom a perspective of the virtual camera 130 positioned as shown inFIG. 1. The display device 210 can be part of an exemplary computingdevice 200. The computing device 200 can be any suitable computingdevice, such as general purpose computing device, a mobile device,smartphone, tablet, laptop, desktop, or other suitable computing device.

As shown, the view of three-dimensional model 110 provides arepresentation of a scene 100 depicting a geographic area. Thethree-dimensional model 110 includes terrain geometry 112 providing arepresentation of the terrain of the geographic area. Thethree-dimensional model 110 also includes building geometry 114 thatprovides a representation of a building in the geographic area.

Vector data 140 is rendered in conjunction with the three-dimensionalmodel 110. The vector data 140 includes road overlays 142 depicting thelocations of roads in the geographic area. The vector data 140 alsoincludes various text annotations 144 depicted in conjunction with thethree-dimensional model 110. Other vector data can be included in therepresentation of the geographic area.

The vector data 140 is texture mapped to a smooth transparent drapinglayer that conforms to the terrain geometry 112. Portions of the smoothtransparent draping layer that do not include vector data are invisibleor are completely transparent. As such, the smooth transparent drapinglayer is not readily visible in the representation of thethree-dimensional model 110 presented in the viewport 215. The vectordata 140 texture mapped to the smooth transparent draping layer,however, appears to be rendered along the surface of the terraingeometry 112 of the three-dimensional model 110.

The smooth transparent draping layer can be occluded by buildinggeometry 114 of the three-dimensional model 110. As a result, vectordata 140 texture mapped to the smooth transparent draping layer can alsobe occluded by the building geometry 114. This is depicted in FIG. 2which shows the building geometry 114 occluding text annotation 144 anda portion of the road overlays 142 texture mapped to the smoothtransparent draping layer.

FIG. 3 depicts a flow diagram of an exemplary method (300) for renderingvector data in conjunction with a three-dimensional model according toan exemplary embodiment of the present disclosure. The method (300) canbe implemented using any suitable computing system, such as the systemdepicted in FIG. 6. In addition, the flow charts of the methods providedherein depict steps performed in a particular order for purposes ofillustration and discussion. One skilled in the art, using thedisclosures provided herein, will appreciate that various steps of anyof the methods discussed herein can be omitted, rearranged, combinedand/or adapted in various ways.

At (302), the method includes presenting a viewport in a user interfaceon a display of a computing device. The viewport defines a space in theuser interface for viewing and navigating a three-dimensional model. Forinstance, FIG. 2 depicts a viewport 215 presented in a user interface205 that allows a user to view and navigate geographic imagery. Theviewport can have any suitable size, shape, or configuration in the userinterface.

At (304) of FIG. 3, the method can include receiving a user inputrequesting a particular view of the three-dimensional model. The userinput can be received using any suitable user input, such as touchinteraction, click interaction, or other suitable user interaction. Theuser input can control the position of a virtual camera relative to thethree-dimensional model. The virtual camera can be used to construct aview specification which specifies what portion of the three-dimensionalmodel is to be rendered in response to the user input.

Referring back to FIG. 3 at (306), a three-dimensional model can berendered in the viewport. For instance, the three-dimensional model canbe rendered in accordance with the view specification. Thethree-dimensional model can provide a representation of a scene, such asa geographic area or other suitable scene. For instance, as shown inFIG. 2, a three-dimensional model 110 of scene 100 is rendered in theviewport 215. The three-dimensional model 110 can include terraingeometry 112 and building geometry 114.

At (308) of FIG. 3, a smooth transparent draping layer is renderedoverlaying at least one surface in the three-dimensional model. Thesmooth transparent draping layer can be rendered overlaying any suitablesurface. For instance, in the three-dimensional model 110 of FIGS. 1 and2, the smooth transparent draping layer 120 is rendered overlayingsurfaces defined by the terrain geometry 112. In particular, the smoothtransparent draping layer conforms to the surface of the terraingeometry 112.

At (310) of FIG. 3, the vector data is texture-mapped to the smoothtransparent draping layer. Texture mapping is a method for addingdetail, surface texture, or color to a three-dimensional model. Texturemapping the vector data to the transparent draping layer applies thevector data to the surface of the transparent draping layer. Manytexture mapping techniques are known for texture mapping data to asurface of a three-dimensional model. Any suitable texture mappingtechnique can be used without deviating from the scope of the presentdisclosure.

Because the transparent draping layer overlays a surface of thethree-dimensional model, texture mapping the vector data to thetransparent draping layer causes the vector data to appear as if thevector data is rendered along a surface of the three-dimensional model.For instance, as shown in FIG. 2, the vector data 140 is texture mappedto a smooth transparent draping layer such that the vector data appearsto be located along a surface of the three-dimensional model 110 of theviewport. In particular, the vector data 140 appears to be located alongthe surface of the terrain geometry 112 of the three-dimensional model110. The transparent draping layer remains invisible for portions of thetransparent draping layer that do not include vector data. For instance,the alpha values for portions of the transparent draping layer can beabout zero such that portions of the transparent draping layer that donot include vector data remain transparent.

Various rendering algorithms can be used to render the vector data inconjunction with the three-dimensional model according to exemplaryaspects of the present disclosure. For instance, in one embodiment, thesmooth transparent draping layer can be rendered with a depth offsetrelative a surface of the three-dimensional model. The depth offset canprovide depth values for the transparent draping layer that are in frontof depth values associated with the surface of the three-dimensionalmodel in a depth buffer associated with the scene. As a result, thetransparent draping layer can be rendered overlaying thethree-dimensional model.

In particular aspects where the three-dimensional model includes terraingeometry and building geometry, such as the three-dimensional model 110of FIGS. 1 and 2, the depth offset for the transparent draping layer canbe provided relative to the terrain geometry. The depth offset for thetransparent draping layer is not provided relative to the buildinggeometry. As a result, depth values in the depth buffer associated withthe building geometry can be in front of depth values associated withthe transparent draping layer. In this way, the transparent drapinglayer can be rendered overlaying the terrain geometry but can beoccluded by the building geometry during rendering of the scene.

FIG. 4 depicts a flow diagram of another exemplary method (400) that canbe used to render a scene according to an exemplary embodiment of thepresent disclosure. The exemplary method (400) of FIG. 4 is particularlysuitable for implementations with terrain geometry and buildinggeometry. The method (400) can be implemented by any suitable computingdevice, such as the client computing device 630 of FIG. 6.

At (402), the method includes rendering the building geometry with afirst stencil value (e.g. zero) in a stencil buffer for pixelsassociated with the building geometry. At (404), the terrain geometry isrendered with a second stencil value (e.g. one) for pixels associatedwith the terrain geometry. The stencil buffer can be an extra bufferassociated with the scene that can be used to limit the area ofrendering.

The rendering method can then clear the depth values in a depth bufferfor all pixels associated with the second stencil value in the stencilbuffer. The depth buffer (i.e. z-buffer) can be used to manage imagedepth coordinates during rendering of the scene. Clearing depth valuesfor pixels in the depth buffer associated with the second stencil valueessentially clears the depth buffer for pixels associated with theterrain geometry.

In one implementation, the rendering method can clear the depth valuesin the depth buffer by rendering a full screen quad for pixelsassociated with the second stencil value (e.g. pixels that fail astencil test) with depth write on (i.e. z-write on) and depth test off(i.e. z-test off) (406). Depth write on (i.e. z-write on) allows depthvalues to be written to the stencil buffer. Depth test off (i.e. z-testoff) indicates that no depth comparison is made prior to writing thedepth values to the stencil buffer. In other words, depth values arewritten to the stencil buffer for pixels associated with the secondstencil value in the stencil buffer regardless of the depth valuesalready stored in the depth buffer. This technique can be used to writethe maximum depth value in the depth buffer for pixels associated withthe second stencil value in the stencil buffer, effectively clearing thedepth values for pixels associated with the building geometry.

At (408), the transparent draping layer is rendered with depth write on(i.e. z-write on) and depth test on (i.e. z-test on). Depth test on(i.e. z-test on) provides for the writing of depth values to portions ofthe depth buffer that pass a depth test (e.g. only writes depth valuesthat are in front of existing depth values in the depth buffer). Becausethe depth buffer has been cleared with respect to pixels associated withthe terrain geometry, the transparent draping layer is rendered in frontof the terrain geometry. The depth buffer has not been cleared withrespect to pixels associated with the building geometry. As a result,the transparent draping layer can be rendered in front of or behind thebuilding geometry depending on the depth values associated with thetransparent draping layer and the building geometry.

At (410), the vector data is texture mapped to the transparent drapinglayer. Portions of the transparent draping layer that do not includevector data can be rendered with an alpha value of about zero such thatthe transparent draping layer remains transparent. Texture mapping thevector data to the transparent draping layer renders the vector datasuch that it appears to be located along a surface of thethree-dimensional model in the viewport.

FIG. 5 depicts an exemplary method (500) for generating a smoothtransparent draping layer according to an exemplary embodiment of thepresent disclosure. The exemplary method (500) can be implemented usingany suitable computing device, such as the server 610 of FIG. 6.

At (502) of FIG. 5, data associated with a three-dimensional model isaccessed. The three-dimensional model can be a stereo reconstructiongenerated from aerial or satellite imagery of a geographic area. Theimagery can be taken by overhead cameras, such as from an aircraft, atvarious oblique or nadir perspectives. In the imagery, features aredetected and correlated with one another. The points can be used todetermine a polygon mesh from the imagery. The three-dimensional modelcan include terrain geometry and building geometry. In certainimplementations, the three-dimensional model can be represented as aheight field. Each pixel in the height field can have a value indicatinga height of the three-dimensional model at the pixel.

At (504), terrain geometry is extracted from the three-dimensionalmodel. Any suitable technique can be used for extracting the terraingeometry from the three-dimensional model. For instance, in oneimplementation, portions of the three-dimensional model can beclassified as either terrain geometry or as non-terrain geometry.Non-terrain geometry can be identified by resampling the model to ahigher resolution. A low pass filter can be run across the resampledmodel. The filtered result can be subtracted from the resampled data toextract only the high pass data. Portions of the high pass data thatexceed a predefined threshold can be classified as non-terrain geometry.The non-terrain geometry can be invalidated in the three-dimensionalmodel to extract the terrain geometry from the three-dimensional model.The terrain geometry can be represented as a terrain height field.

At (506), the terrain geometry is smoothed according to a smoothingalgorithm to generate smooth terrain geometry. The terrain geometry canbe smoothed aggressively using simple image space smoothing algorithms,such as Gaussian smoothing algorithms. The smooth terrain geometry canbe represented as a smooth terrain height field. At (508), the smoothtransparent draping layer is generated from the smooth terrain geometry.For instance, the smooth terrain height field can be processed using ameshing algorithm (e.g. a marching cubes algorithm) to generate a meshfor the smooth transparent draping layer.

At (510), the smooth transparent draping layer is spatially partitionedinto a plurality of discrete geospatial data objects (e.g. discretegeospatial volumes or tiles). Each geospatial data object can store dataassociated with the portion of the transparent draping layer in thegeospatial extent defined by the geospatial data objects. The discretegeospatial data objects can then be stored in a hierarchical tree datastructure, such as a quadtree data structure or an octree data structure(512). The method (500) of FIG. 5 can be performed for each level ofdetail of the three dimensional model so that a different transparentdraping layer can be generated for each level of detail of thethree-dimensional model.

FIG. 6 depicts an exemplary computing system 600 that can be used toimplement the methods and systems for merging three-dimensional modelsaccording to exemplary aspects of the present disclosure. The system 600is a client-server architecture where a server 610 communicates with oneor more client devices 630 over a network 650. The system 600 can beimplemented using other suitable architectures.

The system 600 includes a computing device 610. The computing device 610can be any machine capable of performing calculations automatically. Forinstance, the computing device can include a general purpose computer,special purpose computer, laptop, desktop, integrated circuit, mobiledevice, smartphone, tablet, or other suitable computing device. Thecomputing device 610 can have a processor(s) 612 and a memory 614. Thecomputing device 610 can also include a network interface used tocommunicate with one or more remote computing devices (e.g. clientdevices) 630 over a network 650. In one exemplary implementation, thecomputing device 610 can be a server, such as a web server, used to hosta geographic information system, such as the Google Maps™ and/or theGoogle Earth™ geographic information systems provided by Google Inc.

The processor(s) 612 can be any suitable processing device, such as amicroprocessor, microcontroller, integrated circuit, or other suitableprocessing device. The memory 614 can include any suitablecomputer-readable medium or media, including, but not limited to,non-transitory computer-readable media, RAM, ROM, hard drives, flashdrives, or other memory devices. The memory 614 can store informationaccessible by processor(s) 612, including instructions 616 that can beexecuted by processor(s) 612. The instructions 616 can be any set ofinstructions that when executed by the processor(s) 612, cause theprocessor(s) 612 to provide desired functionality. For instance, theinstructions 616 can be executed by the processor(s) 612 to implement adraping layer module 618 and a chopper module 620.

The draping layer module 618 can be configured to generate a smoothtransparent draping layer according to exemplary aspects of the presentdisclosure. For instance, the draping layer module 618 can be configuredto access a three-dimensional model and extract terrain geometry fromthe three-dimensional model. The draping layer module 618 can beconfigured to smooth the terrain geometry according to a suitablesmoothing algorithm to generate smooth terrain geometry. The drapinglayer module 618 can then generate the transparent draping layer fromthe smooth terrain geometry, for instance, using a suitable meshingalgorithm. The draping layer module 618 can generate a transparentdraping layer for each level of detail of the three-dimensional model.

The chopper module 620 can spatially partition the transparent drapinglayer for each level of detail into a plurality of geospatial dataobjects (e.g. discrete geospatial volumes or tiles). The chopper module620 can then store the discrete geospatial data objects in ahierarchical tree data structure encoded in the memory 614.

It will be appreciated that the term “module” refers to computer logicutilized to provide desired functionality. Thus, a module can beimplemented in hardware, application specific circuits, firmware and/orsoftware controlling a general purpose processor. In one embodiment, themodules are program code files stored on the storage device, loaded intomemory and executed by a processor or can be provided from computerprogram products, for example computer executable instructions, that arestored in a tangible computer-readable storage medium such as RAM, harddisk or optical or magnetic media.

Memory 614 can also include data 622 that can be retrieved, manipulated,created, or stored by processor(s) 612. For instance, memory 614 canstore data 622 associated with the three dimensional model and thehierarchical tree data structure. The data 622 can be stored in one ormore databases. The one or more databases can be connected to thecomputing device 610 by a high bandwidth LAN or WAN, or can also beconnected to computing device 610 through network 650. The one or moredatabases can be split up so that it is located in multiple locales.

The computing device 610 can exchange data with one or more clientdevices 630 over the network 650. Although two clients 630 areillustrated in FIG. 4, any number of clients 630 can be connected to thecomputing device 610 over the network 650. The client devices 630 can beany suitable type of computing device, such as a general purposecomputer, special purpose computer, laptop, desktop, integrated circuit,mobile device, smartphone, tablet, or other suitable computing device.

Similar the computing device 610, a client device 630 can include aprocessor(s) 632 and a memory 634. The memory 634 can store informationaccessible by processor(s) 632, including instructions 636 that can beexecuted by processor(s) 632 and data 638. The instructions 636 can beany set of instructions that when executed by the processor(s) 632,cause the processor(s) 632 to provide desired functionality. Forinstance, the instructions 636 can be executed by the processor(s) 632to implement a user interface module and a renderer module.

The user interface module can be configured to present a viewport in auser interface on a display device 640. The renderer module can beconfigured to render vector data in conjunction with thethree-dimensional model in the viewport according to any of theexemplary methods for rendering vector data in conjunction withthree-dimensional models disclosed herein. For instance, the renderermodule can be configured to render the three-dimensional model in theviewport and to render a transparent draping layer overlaying thethree-dimensional model. The renderer module can be further configuredto texture map vector data to the transparent draping layer such thatthe vector data appears to be located on a surface defined by thethree-dimensional model.

Responsive to a request for information, the computing device 610 canencode data in one or more data files and provide the data files to theclient devices 630 over the network 650. The network 650 can be any typeof communications network, such as a local area network (e.g. intranet),wide area network (e.g. Internet), or some combination thereof. Thenetwork 650 can also include a direct connection between a client device6300 and the computing device 610. In general, communication between thecomputing device 610 and a client device 430 can be carried via networkinterface using any type of wired and/or wireless connection, using avariety of communication protocols (e.g. TCP/IP, HTTP, SMTP, FTP),encodings or formats (e.g. HTML, XML), and/or protection schemes (e.g.VPN, secure HTTP, SSL).

While the present subject matter has been described in detail withrespect to specific exemplary embodiments and methods thereof, it willbe appreciated that those skilled in the art, upon attaining anunderstanding of the foregoing may readily produce alterations to,variations of, and equivalents to such embodiments. Accordingly, thescope of the present disclosure is by way of example rather than by wayof limitation, and the subject disclosure does not preclude inclusion ofsuch modifications, variations and/or additions to the present subjectmatter as would be readily apparent to one of ordinary skill in the art.

What is claimed is:
 1. A computer-implemented method for renderingvector data in conjunction with a three-dimensional model, comprising:presenting a viewport in a user interface on a display device; renderingthe three-dimensional model in the viewport; rendering a transparentdraping layer overlaying the three-dimensional model; and texturemapping the vector data to the transparent draping layer such that thevector data appears to be located along a surface of thethree-dimensional model in the viewport.
 2. The computer-implementedmethod of claim 1, wherein the transparent draping layer conforms to asurface of the three-dimensional model.
 3. The computer-implementedmethod of claim 1, wherein the transparent draping layer has beengenerated based at least in part on a smoothing algorithm.
 4. Thecomputer-implemented method of claim 1, wherein the three-dimensionalmodel comprises terrain geometry providing a representation of terrainof a geographic area and building geometry providing a representation ofone or more buildings in the geographic area.
 5. Thecomputer-implemented method of claim 4, wherein the transparent drapinglayer overlays the terrain geometry.
 6. The computer-implemented methodof claim 5, wherein the transparent draping layer conforms to theterrain geometry.
 7. The computer-implemented method of claim 4, whereinrendering the transparent draping layer comprises rendering thetransparent draping layer with a depth offset relative to the terraingeometry.
 8. The computer-implemented method of claim 4, wherein thevector data is occluded by the building geometry when the vector data istexture mapped to the transparent draping layer.
 9. Thecomputer-implemented method of claim 8, wherein rendering thethree-dimensional model in the viewport comprises: rending the buildinggeometry in the viewport with a first stencil value in a stencil bufferfor pixels associated with the building geometry; rendering the terraingeometry in the viewport with a second stencil value in a stencil bufferfor pixels associated with the building geometry; clearing a depthbuffer at pixels associated with the second stencil value in the stencilbuffer.
 10. The computer-implemented method of claim 9, wherein clearingthe depth buffer at pixels associated with the second stencil valuecomprises writing a maximum depth value to the depth buffer at allpixels associated with the second stencil value with depth write anddepth test off.
 11. The computer-implemented method of claim 10, whereinrendering the transparent draping layer comprises rendering thetransparent draping layer with depth test on.
 12. Thecomputer-implemented method of claim 1, wherein an alpha valueassociated with a portion of the transparent draping layer with novector data is zero.
 13. The computer-implemented method of claim 1,wherein the vector data comprises text data, road data, or overlay data.14. The computer-implemented method of claim 1, wherein thethree-dimensional model is a stereo reconstruction.
 15. A computingsystem for rendering vector data in conjunction with a three-dimensionalmodel of a geographic area, the system comprising a processor and adisplay device, the processor configured to implement one or moremodules, the modules comprising: a user interface module implemented bythe processor, the user interface module configured to present aviewport in a user interface on the display device; and a renderermodule implemented by the processor, wherein the renderer module isconfigured to render the three-dimensional model in the viewport, therenderer module further configured to render a transparent draping layeroverlaying the three-dimensional model; wherein the renderer module isfurther configured to texture map the vector data to the transparentdraping layer such that the vector data appears to be located on asurface defined by the three-dimensional model.
 16. The computing systemof claim 15, wherein the three-dimensional model comprises terraingeometry providing a representation of terrain of a geographic area andbuilding geometry providing a representation of one or more buildings inthe geographic area.
 17. The computing system of claim 16, wherein thetransparent draping layer conforms to the terrain geometry.
 18. Thecomputing system of claim 16, wherein the vector data is occluded by thebuilding geometry when the vector data is texture mapped to thetransparent draping layer.
 19. A non-transitory computer-readable mediumstoring computer-readable instructions for execution by one or moreprocessors the when executed by the one or more processors cause the oneor more processors to perform operations for rendering vector data inconjunction with a three-dimensional model of a geographic area, thethree-dimensional model comprising terrain geometry associated withterrain of the geographic area and building geometry associated with oneor more buildings in the geographic area, the operations comprising:presenting a viewport in a user interface on a display device; renderingthe three-dimensional model in the viewport; rendering a transparentdraping layer conforming to the terrain geometry of thethree-dimensional model; and texture mapping the vector data to thetransparent draping layer such that the vector data appears to belocated along a surface of the three-dimensional model in the viewport,the vector data being occluded at least in part by the building geometryin the three-dimensional model.
 20. The non-transitory computer-readablemedium of claim 19, wherein the operation of rendering thethree-dimensional model in the viewport comprises: rending the buildinggeometry in the viewport with a first stencil value in a stencil bufferfor pixels associated with the building geometry; rendering the terraingeometry in the viewport with a second stencil value in a stencil bufferfor pixels associated with the building geometry; and clearing a depthbuffer at pixels associated with the second stencil value in the stencilbuffer; wherein the transparent draping layer is rendered after clearingthe depth buffer with depth write on and depth test on.